Yazarlar
- Tozlu, Alperen(13)
- Ergün, Mustafa(11)
- Artar, Musa(10)
- Cuce, Erdem(9)
- Cuce, Pinar Mert(8)
- Yurdakul, Muhammet(8)
- Imamoglu, Ilyas Kays(7)
- Esmer, Yusuf(6)
- Isik, Cem(6)
- Ongan, Serdar(6)
- Can, Ömer(5)
- Guclu, Tamer(5)
- Kahveci, Hakan(5)
- Tayfur, Bilal(5)
- Yilmaz, Fatih(5)
- Ates, Sevket(4)
- Guler, Evrim(4)
- Gökçe, H.S.(4)
- Karakus, Murat(4)
- Tapkın, Serkan(4)
- Tercan, Emre(4)
- Çaglar, Hakan(4)
- Özahi, Emrah(4)
- Abdioglu, Murat(3)
- Abusoglu, Aysegul(3)
- Altuntas, Serkan(3)
- Ateş, Şevket(3)
- Ayberkin, Doruk(3)
- Aydin, Rahman(3)
- Cakici, Ziya(3)
- Cakir, Mehmet(3)
- Carbas, Serdar(3)
- Dereli, Turkay(3)
- Engin, Mustafa Alptekin(3)
- Gökçe, H. Süleyman(3)
- Güngör, Okan(3)
- Kiral, Adnan(3)
- Kuziboev, Bekhzod(3)
- Murat, Yetis Sazi(3)
- Okur, Fatih Yesevi(3)
Yayınlar
- Derleme MakaleAçık Erişim2024Scopus SJRQ2Review of In Situ Detection and Ex Situ Characterization of Porosity in Laser Powder Bed Fusion Metal Additive Manufacturing
Aydogan, Beytullah; Chou, Kevin
Over the past decade, significant research has focused on detecting abnormalities in metal laser powder bed fusion (L-PBF) additive manufacturing. Effective online monitoring systems are crucial for enhancing process stability, repeatability, and the quality of final components. Therefore, the development of in situ detection mechanisms has become essential for metal L-PBF systems, making efficient closed-loop control strategies to adjust process parameters in real time vital. This paper presents an overview of current in situ monitoring systems used in metal L-PBF, complemented by ex situ characterizations. It discusses in situ techniques employed in L-PBF and evaluates the applicability of commercial systems. The review covers optical, thermal, acoustic, and X-ray in situ methods, along with destructive and non-destructive ex situ methods like optical, Archimedes, and X-ray characterization techniques. Each technique is analyzed based on the sensor used for defect detection and the type or size of defects. Optical in situ monitoring primarily identifies large defects from powder bed abnormalities, while thermal methods detect defects as small as 100 µm and keyholes. Thermal in situ detection techniques are notable for their applicability to commercial devices and efficacy in detecting subsurface defects. Computed tomography scanning excels in locating porosity in 3D space with high accuracy. This study also explores the advantages of multi-sensor in situ techniques, such as combining optical and thermal sensors, and concludes by addressing current research needs and potential applications of multi-sensor systems.
AtıfScopus23WoS22OpenAlex28
İncele - MakaleYalnız künye2024Scopus SJRQ2Optimization, Characterization, and Carbon Footprint Analysis of Alkali Activated Waste Tuff and Fly Ash Mixtures for Deep Mixed Columns
Kamiloğlu, Hakan Alper; Yilmaz, Fatih
Deep soil mixing (DSM) applications are one of the widely known soil stabilization techniques which can be applied to a wide range of soil types. Cement and lime are the major materials used as binders for DSM applications. However, as conventional binders lead to emit a large amount of CO2 during production, eco-friendly binders suitable for DSM applications have become prominent. Alkali-activated materials are good alternatives to conventional binders. This study was intended to investigate the usability of zeolite rich tuff wastes as an alkali-activated binder in DSM columns. Within this scope, the waste tuff and C-type fly ash mixture were used as an alkali-activated binder, and 10 M NaOH solution was used as an activator. Response surface methodology (RSM) was employed in experimental design to determine optimum components to obtain maximum unconfined compression strength and investigate the interaction between stabilization agents. From the RSM analysis the optimum ratios of activator (X1), waste tuff (X2), and precursor (X3) were determined as; X1 = 0.251, X2 = 0.548, and X3 = 0.538 for maximum UCS. UCS, mineralogical and microstructural characterization (XRF, XRD, SEM, EDX, FTIR) was performed for the DSM samples prepared considering the optimized components. It was determined that the UCS values of the 3, 7, and 28-day cured samples stabilized by considering the optimum values gave UCS values approximately 3 to 5 times higher than the lower limit values recommended by FHWA. As a result of mineralogical and microstructural investigation, the reason for the strength increase in the samples can be attributed to the formation of geopolymeric gel between the soil particles by tuff waste and fly ash activated with alkaline activator. Carbon footprint analyses were performed for 1m3 DSM columns produced with alkali-activated binders and ordinary Portland cement (OPC). From the analyses it was seen that the carbon footprint of the DSM column produced using alkali activated binders is lower than that of the DSM column obtained with OPC. After the general evaluation of the study, it is seen that the hypothesis that waste tuff can be used as environmentally safe alkali-activated binders instead of traditional binders is supported.
AtıfScopus6OpenAlex6İncele - MakaleAçık Erişim2024Scopus SJRQ4PREDICTION OF TURKEY'S COTTON SOCK EXPORTS TO GERMANY USING DEEP LEARNING APPROACH; [TÜRKİYE'NİN ALMANYA'YA PAMUKLU ÇORAP İHRACATININ DERİN ÖĞRENME YAKLAŞIMI İLE TAHMİNİ]
Özbek, Ahmet; Teke, Çağatay
Cotton socks are a strategic export product for Turkey. Therefore, the aim of this study is to forecast Turkey's exports to Germany, the world's largest cotton socks market. In order to achieve this objective, the determinants of exports were identified by analysing the literature. Then, expert opinion was sought to determine the importance of these factors for Turkey's cotton socks exports to Germany. Using the deep learning model created from the factors determined as a result of the expert opinion, the prediction of the export of Turkish socks to Germany was realised. A success rate of 96% was achieved with the prediction.
AtıfScopus1OpenAlex1TR Dizin1
İncele - MakaleAçık Erişim2024Scopus SJRQ1Evaluation of Dynamic and Fatigue Behavior of Damaged Steel Beams Strengthened with Different Types of Techniques and a New Strengthening Method Proposal
Ergün, Mustafa; Ateş, Şevket
In recent years, the use of carbon fiber-reinforced polymers to strengthen fatigue-damaged steel beams has increased significantly as an alternative to traditional methods due to their easy application to the damaged area, lightweight, durability, and sustainability. In addition to all these positive contributions, there are some disadvantages, such as debonding damage under loading. These disadvantages encourage researchers to produce new materials or apply materials used for other purposes in other fields for fatigue damage. In this paper, an alternative new strengthening technique is mentioned to improve the dynamic and fatigue behavior of fatigue-damaged steel beams. This technique is a strengthening application made using epoxy-based filler and carbon fiber-reinforced polymer fabric. Numerical and experimental studies are carried out on fatigue-damaged steel beams by applying this new technique and using different carbon fiber-reinforced polymers, such as a single and double layer of fabric and a single plate layer. The most significant improvement in dynamic behavior occurred on the specimen, strengthened with this newly proposed technique. In contrast, the lowest increase occurs on the sample strengthened with a single layer of fabric. While the lowest increase arises on the sample strengthened with a single layer of fabric in terms of fatigue life, the most significant progress in fatigue behavior makes on the sample strengthened with a single plate layer. As a result of comparing the results, it is concluded that this new strengthening technique could be an essential alternative to the currently used strengthening methods.
AtıfScopus2WoS2OpenAlex3İncele - MakaleAçık Erişim2024Scopus SJRQ1A case study comparing seismic retrofitting techniques for a historically significant masonry building's minaret
Kiral, Adnan; Ergün, Mustafa; Tonyali, Zeliha; Artar, Musa; Şentürk, İdris
Historical masonry structures are extremely susceptible to earthquakes due to their characteristic features. Seismic performance and corresponding damage patterns vary between these buildings. Even though the main structure was undamaged, many minarets suffered damage or collapsed due to the transmission of large forces from the main mass to the minaret and the abrupt changes in cross-section due to the geometry of the minaret. This study uses an ancient masonry mosque as a case study, whose minaret and main building are constructed as a single structure. The mosque's minaret under seismic excitation is the focus of this study. The adopted model is called Alaeddin Bey Mosque in Muş, Türkiye. The seismic performance assessment of the minaret, considering various retrofitting options, is mainly based on four critical parameters: base shear, acceleration, displacement, and maximum tensile forces in all three dimensions. The analyzed retrofitting methods include base isolation located in the basement of the mosque, viscous dampers placed only in the upper part of the minaret, Carbon Fiber-Reinforced Polymer fabric fitted to only the minaret, and steel plates applied to only the minaret. Representative structural models of the mosque have been modelled with SAP2000 software. The main novelty of this study is the use of viscous dampers in the minaret. It is the first time a design methodology has been introduced for viscous damper applications in minarets. This methodology aims to prevent local damage to the minaret due to the forces generated by the dampers, while also considering the constraints of limited internal space within the minaret. The finding of this study shows that viscous damper application yields significantly better results compared to the application of Carbon Fiber-Reinforced Polymer fabric and steel plates. However, although base isolation reduces the tensile stress values throughout the entire mosque to levels well below the material's strength, viscous damper application in the minaret significantly reduces tensile stresses only in the minaret. As a result, viscous dampers are recommended for damage reduction in the minaret only. Otherwise, base isolation should be considered for reducing stress values throughout the entire mosque including the minaret. This study contributes towards the development of new seismic retrofitting methods for historic masonry buildings ‘minaret.
AtıfScopus26WoS26OpenAlex24İncele - MakaleYalnız künye2024Scopus SJRQ1Intelligent detection of airport pavement subtle crack based on one-stage anchor-free deep neural network
Yuan, Bo; Tapkın, Serkan; Pei, Lili; Tercan, Emre; Zhao, Kaiyue; Li, Wei
To solve issues with low-detection accuracy and high-missed detection rate in subtle pavement cracks, this research proposed an intelligent detection method based on a one-stage anchor-free deep neural network, which consists of a feature extraction network, detection neck, and detection head. The feature extraction network with an extended deep attention network is responsible for extracting the features and output at different scales. The detection neck containing the special spatial pyramid structure fuses the contextual information of different scales to improve the abstract features. The detection head is composed of the anchor-free mechanism with decoupling property and the reparameterized structure to improve the detection accuracy and balance the algorithm complexity. The experimental results demonstrate that the Precision, Recall, and F1-Score are, 92.74%, 91.92%, and 0.9233 respectively. It has advantages over the most advanced one-stage detection method. Based on testing results, it has prominent stability and robustness for subtle pavement crack detection.
AtıfScopus1WoS1OpenAlex2İncele - MakaleYalnız künye2024Scopus SJRQ1Evaluation of the seismic performance pre- and post-restoration of a masonry clock tower's FE model updated via experimental and optimization methods
Ergün, Mustafa; Tayfur, Bilal
This article presents comprehensive numerical and partial experimental studies to determine the seismic performance of the recently restored masonry clock tower in Bayburt before and after restoration. The numerical dynamic characteristics of the structure are obtained by free vibration analysis conducted on the preliminary finite element model, while the experimental ones are determined through ambient vibration testing. The ultimate finite element models reflecting the actual state of the structure pre- and post-restoration are created through a model updating process based on the principle of minimizing the differences between numerical and experimental dynamic properties via the Tabu Search Algorithm. Dynamic analyses of the models are carried out by the mode superposition method in the time domain, using eleven earthquake ground motion records selected considering the tectonic structure of the region and scaled to the design spectrum explicitly established to the site. Seismic responses are evaluated based on displacement, maximum-minimum principal stress, and maximum-minimum principal strain. The maximum principal stress value, the most critical parameter jeopardizing the safety of masonry structures, is 2.069 MPa before the restoration reaches 2.489 MPa, with an increase of approximately 20.3 % after the restoration. Since this value is less than the tensile strength of the masonry material, 3.120 MPa, it is not at a level that poses any risk to the structure. Other structural reactions also remain below the limit values. Therefore, according to today's seismic hazard analysis criteria, it can be said that the clock tower is safe. However, the North Anatolian Fault Zone, with high tectonic activity passing just south of the city, has the potential to produce severe earthquakes that may affect the region in the future. Therefore, it is necessary to periodically monitor the seismic behaviors of the historical masonry structures in Bayburt and take essential precautions based on the results.
AtıfScopus12WoS11OpenAlex13İncele - MakaleYalnız künye2024Scopus SJRQ1Design, modelling, environmental, economic and performance analysis of parabolic trough solar collector (PTC) based cogeneration systems assisted by thermoelectric generators (TEGs)
Cuce, Pinar Mert; Guclu, Tamer; Cuce, Erdem
Concentrating solar power systems (CSP) is a very efficient technology for clean and renewable energy production. It basically works on the principle of focusing the sun's rays with the help of a reflective surface. There are two types of CSP systems: point-focused and line-focused. Point-focused ones are parabolic dish collectors and solar towers. Line-focused ones are parabolic trough collectors (PTCs) and linear Fresnel reflectors. It is possible to reach focus temperatures over 1000 °C with point-focused CSPs. Line-focused CSP systems are used to obtain thermal and electrical energy at temperatures below 500 °C. Among CSP technologies, PTCs are widely preferred. While it can be used alone, it can also be used in combination with other power generation systems by creating hybrid systems. In this regard, hybrid PTC/TEG energy systems created with thermoelectric generators (TEGs) come to the fore. These systems have higher electrical and thermal efficiency values compared to traditional PTCs. In this study, CSP systems, PTCs, TEGs and hybrid solar energy systems-based PTCs were examined in detail. It is concluded from the study that the total thermal efficiency of PTC-TEG hybrid systems can be enhanced by up to %70 with respect to PTC systems.
AtıfScopus42WoS40OpenAlex37İncele - MakaleYalnız künye2024Scopus SJRQ3Capacity-spectrum push-over analysis of rock-lining interaction model for seismic evaluation of tunnels
Majidian, Sina; Tapkın, Serkan; Tercan, Emre
Evaluation of tunnel performance in seismic-prone areas demands efficient means of estimating performance at different hazard levels. The present study introduces an innovative push-over analysis approach which employs the standard earthquake spectrum to simulate the performance of a tunnel. The numerical simulation has taken into account the lining and surrounding rock to calculate the rock-tunnel interaction subjected to a static push-over displacement regime. Elastic perfectly plastic models for the lining and hardening strain rock medium were used to portray the development of plastic hinges, nonlinear deformation, and performance of the tunnel structure. Separately using a computational algorithm, the non-linear response spectrum was approximated from the average shear strain of the rock model. A NATM tunnel in Turkey was chosen for parametric study. A seismic performance curve and two performance thresholds are introduced that are based on the proposed nonlinear seismic static loading approach and the formation of plastic hinges. The tunnel model was also subjected to a harmonic excitation with a smooth response spectrum and different amplitudes in the fully-dynamic phase to assess the accuracy of the approach. The parametric study investigated the effects of the lining stiffness and capacity and soil stiffness on the seismic performance of the tunnel.
AtıfScopus1WoS1OpenAlex1İncele - MakaleAçık Erişim2024Scopus SJRQ2Investigating the Effect of Polypropylene Fiber on Mechanical Features of a Geopolymer-Stabilized Silty Soil
Kamiloğlu, Hakan A.; Kurucu, Kutluhan; Akbaş, Dilek
This study investigates the stabilization of silty soil using alkali-activated fly ash and fibers with lengths of 3 mm and 12 mm. The study examines the effects of hybrid fiber length, fiber content, fly ash content, and activator content on the mechanical properties of the geopolymerstabilized samples. The objectives of this paper are 1) to examine the effect of activator content and fly ash content on the UCS, Al/Si ratio, and SiO2/Na2O ratio of the stabilized samples using a statistical approach, 2) to investigate the effect of hybrid fiber length on UCS, secant modulus, flexural strength, toughness, and flexural load-deformation characteristics of the stabilized soil. A statistical approach was employed to investigate the relationship between fly ash content, alkali activator content, and UCS value. Optimal fly ash content and alkali activator content were determined based on the statistical model. The geopolymer structure of the stabilized soil was characterized via SEM, EDS, XRD, and FTIR analyses. The effects of fly ash and alkali activator content on UCS, Al/Si ratio, and SiO2/Na2O ratio were determined using the derived statistical model. The study demonstrated that activator content, a critical factor in compaction, significantly influences the UCS value, as much as the effect of the Si/Al and SiO2/Na2O ratios. Additionally, variations in fly ash content led to an increase in the UCS value of up to 15%. Moreover, changing the activator content resulted in a maximum 12-fold increase in UCS value. Incorporating hybrid fibers for stabilization led to higher secant modulus (up to 30%), flexural strength (up to 6%), and ductility without compromising UCS.
AtıfScopus20WoS17OpenAlex18İncele - MakaleAçık Erişim2024Scopus SJRQ2Effects of Recycled Asphalt Material and Natural Pozzolan as Additives of Hot-Mix Asphalt: A Field Study
Yilmaz, Bahadır; Şentürk, Mehmet Akif
Using existing resources more efficiently and effectively becomes important currently. The question of how to make the best use of resources arises in the choice between constructing new roads and improving deteriorated existing roads. It is also important to reduce the amount of consumption and cost of materials. This has emerged the need to use waste materials by recycling and reusing. In this study, a new hot-mix asphalt (HMA) mixture was developed using recycled asphalt pavement (RAP), which was obtained by excavating the surface of a road at the end of its service life, together with a waste material namely natural pozzolan (NP). The final obtained mixture was used as a wear layer on an active highway. Core specimens were extracted from the paved layer for one year and subjected to dynamic and mechanical laboratory tests. Adding NP improved the resistance of the HMA mixture under heavy seasonal effects and traffic loads. In addition, NP increased the tensile strength, making the HMA mixture more resistant to deformation than control and RAP HMA mixtures. Dynamic creep test results showed that the control asphalt mixture had the most deformation and that the RAP mixture with NP had the least. According to the laboratory results, NP addition increased the stability value of the control mixture by 40%. Especially in cold seasons, the role of NP was more evident. In the performance tests that were applied on core samples taken from the field, ITS values for September increased by 98%, and the deformation values obtained as a result of the dynamic creep test decreased by 12%. In summary, adding NP to RAP HMA improves the performance of the pavement and the cost-effectiveness of the environmentally friendly use of RAP in HMA.
AtıfScopus1WoS1OpenAlex1İncele - MakaleAçık Erişim2024Scopus SJRQ1Energy-driven TBM health status estimation with a hybrid deep learning approach
Li, Yongsheng; Zhang, Limao; Pan, Yue; Tapkın, Serkan; Song, Xieqing
This study provides a hybrid deep learning approach that enables the researchers to estimate the Tunnel Boring Machine (TBM) health status during excavation process using energy consumption data. By analyzing the energy forms and paths in the tunneling process, the key energy factors' consumption performance behavior affecting TBM safety is identified. The Ensemble Empirical Mode Decomposition (EEMD) method and a Convolution neural network-Long short term memory-Depth Neural Network (CNN-LSTM-DNN, CLDNN) model are integrated for Health Performance Parameter (HPP) prediction. A classification method is constructed by the Generative Adversarial Imputation Networks (GAIN) model for health status estimation. The SHapley Additive exPlanations (SHAP) method is performed to quantify the relationships between energy consumption and system health status. A tunneling case in Singapore is used to test the effectiveness of the developed methodology. It is found that (1) the proposed method provides TBM cutter wear and cooling oil prediction with a R-square (R2) of 0.8591 and 0.8727, respectively, and (2) classification results indicate that the estimation F1-score of 0.9863 can be achieved based on health status evaluation indicator (HSEI). The novelty of the proposed approach lies in its capabilities of (1) fully extracting and utilizing the energy consumption information in every regard to predict TBM health performance; (2) providing a good one-step-ahead health status estimation for the TBM excavation process. Therefore, this study proposes a feasible direction for the application of energy consumption data in TBM health status estimation.
AtıfScopus17WoS15OpenAlex17İncele - MakaleAçık Erişim2024Scopus SJRQ1Thermal and energy analysis of a novel solar updraft tower design with divergent chimney and convergent collector concept: CFD analysis with experimental validation
Cuce, Pinar Mert; Saxena, Abhishek; Cuce, Erdem; Kontoleon, Karolos J.; Oztekin, Erman K.; Shaik, Saboor; Guo, Shaopeng
The fact that energy sources are heavily dependent on fossil fuels increases the need for alternative energy day by day. Solar energy is the most popular alternative energy source with massive potential. Solar chimney power plants (SCPP) are one of the systems of interest based on solar energy. SCPP systems are rare systems that can provide 24-hour power output. Their performance has been the subject of constant research since the first pilot plant in Manzanares. Design is crucial for performance figures of SCPPs, and the limitation of climatic parameters causes the system to be approached with different designs. This study makes a 3D CFD model by combining the divergent chimney and convergent collector structure based on the first pilot plant. The solar ray tracing algorithm and the RNG k-e turbulence model are applied and the model equations are solved under dynamic conditions with the reliable software ANSYS FLUENT. After the mesh-independent solution of the model is complete, it is validated with experimental data. The two cases are compared for solar radiation of 1000 W/m2 and environmental temperature of 293 K. A power output of 50.51 kW is achieved for standard pilot sizing. With the new model, the power output rises to 146.34 kW. It is seen that the divergent chimney and convergent collector affect the airflow in the system, increasing the maximum air velocity to 19.363 m/s. In parallel with the experimental data, it is seen that the temperature on the ground exceeds 360 K in the CFD results.
AtıfScopus17WoS12OpenAlex14İncele - MakaleYalnız künye2023Mekânsal Panel Modelleri Kullanılarak Yenilenebilir Enerji Tüketimi, Çevresel Bozulma ve Büyüme İlişkisinin İncelenmesi: Balkan Ülkelerinden Kanıtlar
Arı, Ari; Bayramoglu, Turgut; Sayar, Ramazan
Amaç: Bu çalışmayla karbon salınımının Balkan ülkeleri ve Türkiye'nin büyümesine etkisinin olup olmadığının, eğer varsa, bu etkinin ne yönde ve ne yoğunlukta olduğunun bulunması amaçlanmıştır. Yöntem: Bu çalışmada karbon emisyonları ve yenilenebilir enerji üretiminin Türkiye ve 12 Balkan ülkesinin büyümesine etkileri analiz edilmiştir. Çalışmada mekânsal etkileşimleri ortaya çıkarabilmek için Mekânsal Otokorelasyon Analizi yapılmıştır. Büyümeyi etkileyen faktörleri incelemek için ise Havuzlanmış En Küçük Kareler yöntemi kullanılmıştır. Bulgular: Çalışmanın sonuçlarına göre Balkan ülkelerinde yenilenebilir enerjinin büyüme üzerindeki olumsuz etkisinin, yenilenebilir enerjinin henüz gelişme aşamasında olması ve üretimdeki payının hala düşük olmasından kaynaklandığı söylenebilir. Yenilenebilir enerji sektöründeki yatırımların sınırlı olması yenilenebilir enerji sektörünün yavaş yayılmasına neden olmaktadır. Özgünlük: Çalışmada farklı bir yöntem olarak mekânsal panel modellerinin kullanılması ve kapsamın Türkiye ile sınırlı tutulmayıp tüm Balkan ülkelerini de kapsaması bu çalışmanın özgün değerini oluşturmaktadır.
AtıfOpenAlex1İncele - MakaleAçık Erişim2023Yüksek mertebe sonlu eleman modeliyle fonksiyonel derecelendirilmiş kirişlerin serbest titreşim ve statik analizi
Turan, Muhittin; Hacıoğlu, Mahmut İlter
Bu çalışmada, fonksiyonel derecelendirilmiş (FD) kirişlerin yüksek mertebeden kayma deformasyonlu kiriş teorisine dayalı sonlu eleman yöntemiyle serbest titreşim ve statik analizleri incelenmiştir. Sonlu elemanlar yöntemi için 5 düğümlü ve 16 serbestlikli bir sonlu eleman önerilmiştir. FD kirişin malzeme özelliği kiriş kalınlığı boyunca belli bir kuvvet kuralı fonksiyona bağlı olarak değişmektedir. Lagrange eşitliği ile denge denklemleri türetilmiştir. Farklı kuvvet fonksiyonu üst indisine (p), farklı sınır şartlarına ve farklı narinliklere (L/h) göre FD kirişin boyutsuz doğal frekansları, boyutsuz yer değiştirmeleri, boyutsuz normal ve kayma gerilmeleri elde edilmiştir. Çalışmadan elde edilen sonuçlar literatür ile karşılaştırılmış ve önerilen sonlu elemanın FD kirişler için oldukça uyumlu sonuçlar verdiği görülmüştür. Önerilen yüksek mertebeden kayma deformasyonlu kiriş elemanının bu tip problemlerin çözümünde kullanılabileceği sonucuna varılmıştır. Kuvvet fonksiyonu üst indis değerinin artmasıyla birlikte boyutsuz doğal frekanslar azalmakta, boyutsuz maksimum yer değiştirmeler ise artmaktadır.
AtıfOpenAlex3TR Dizin1İncele - MakaleAçık Erişim2023The Blockchain Usage and Current Trends in the Tourism Sector: A Conceptual Research
Esmer, Yusuf; Medeni, Ihsan Tolga; Medenı, Tunç Durmus; Erol, İsmail
Today, with changes and developments in technology, there are changes in concepts, uses, and even in daily life, and it is seen that this situation permeates all areas of life. In this context, many new types of technology have emerged. Blockchain is one of these technologies and is one of the applications in the tourism sector in human life. Therefore, it is necessary to examine this phenomenon by focusing on the studies carried out to perceive the possible results of both software and hardware applications realized with technologies developed on blockchain, and to understand the opportunities that may arise in the tourism sector. Accordingly, in this study, particularly studies on the areas where tourism and blockchain intersect are examined and a conceptual analysis is conducted on these topics by determining the topics of blockchain use in Europe and the USA from the perspective of basic accommodation services, tourist data, medical tourism, and global application areas. Based on this academic framework, an application suggestion for Türkiye is also provided.
- MakaleYalnız künye2023Kükürt Polimer Betonların Basınç Dayanımı ve Elastisite Modülüİlişkisinin Yönetmelikler Açısından Karşılaştırılması
Ozturk, Onur; Öner, Adnan; Karadeniz, Murat
Üstün mekanik ve durabilite özellikleri ile kükürt polimer betonlar (KPB) geleneksel Portland çimento betonlarına (PÇB) alternatif yapı malzemesi olarak son yıllarda ön plana çıkmıştır. Betonun önemli bir tasarım parametresi olan elastisite modülü ile ilgili araştırmaların KPB’ler açısından literatürde yetersiz olduğu ve standartlarda önerilen tahmin modellerinde halen göz önünde bulundurulmadığı görülmektedir. Bundan dolayı bu çalışma kapsamında, KPB’lerin basınç dayanımıelastisite modülü ilişkisinin uluslararası standartlarca önerilmiş olan analitik modeller ve geleneksel PÇB’ler ile karşılaştırmalı olarak incelenmesi amaçlanmıştır. Deneysel çalışma sonucunda KBP’lerin elastisite modüllerinin, benzer basınç dayanımı değerlerine sahip PÇB’lere göre daha düşük değerlerde kaldığı belirlenmiştir. PÇB’ler için standartlarda önerilmiş olan analitik modellerin KPB’lerin elastisite modülleri tahmininde ACI 363R-92 ve NS 3473 standartları haricinde yaklaşık değerler elde edilemediği görülmüştür. Deneysel çalışmadaki veriler kullanılarak bu çalışma kapsamında yeni bir analitik model önerilmiştir. Önerilen analitik model, yakın sonuç veren standartlardaki modeller ile istatistiki olarak karşılaştırmalı incelenmiş ve önerilen modelin deneysel değerlere en yakın sonuçları verdiği belirlenmiştir
- MakaleAçık Erişim2023Farklı Bayburt Taşı (Tüfit) Boyutlarını Taşıyan Helezonun Doğal Frekans Değişiminin Belirlenmesi
Erbayrak, Engin; Kırar, Burhan
Helezon milin dönme hareketi ile tozu veya çok küçük tanecikli partikülleri taşıyan mekanizmaya helezon konveyör denir. Helezon konveyörlerin çalışma prensibi silindirik bir boru içerisine yerleştirilmiş helezon milin motor gücü ile dönmesi sayesinde toz partiküllerinin taşınmasıdır. Taşıma işlemi toz taneciklerini mekanizmanın tepesindeki besleme borusundan konveyöre helezon milinin kanatlarına (heliks) aktarılması ile olmaktadır. Bu çalışmada vidalı konveyörün ölçekli bir prototipi üretilmiştir. Prototip kullanılarak farklı boyutlardaki Bayburt taşı (Tüfit) taşınmış ve taşıma sırasındaki doğal frekans değişimleri ölçülmüştür. Bayburt taşının ince partiküllerin de doğal frekans değeri en düşük belirlenirken (15.67 Hz), kaba partiküllerde ise doğal frekans değeri yüksek belirlenmektedir (20.32 Hz). Bu durum zorlanmış titreşimin bir örneği olan bu ölçüm için beklenen bir durumdur. Hacimsel boyutu artan partiküllerin ağırlıklarının da artmasıyla beraber meydana getirdikleri dış kuvvet değerleri de artmaktadır. Kütle değerindeki artış ve dinamik yüklerdeki değişim doğal frekans değerini artırmıştır. Partikül boyutlarının inceden kalına doğru artmasıyla beraber doğal frekans değerleri de yüzde 10-15 aralığında arttığı gözlemlenmiştir. Sonuç olarak, konveyörde taşınan parçacıkların boyutlarının sistemin doğal frekans değerini belirlemede önemi olduğu belirlenmiştir.
- MakaleAçık Erişim2023Yönetişim, İnovasyon ve Ekonomik Büyüme Arasındaki İlişkiler: Gelişmiş ve Gelişmekte Olan Ülke Örnekleri
Özdemir, Dilek; Imamoglu, Ilyas Kays
Ülkelerarası gelir farklılıkları iktisat biliminin temel inceleme alanına girmektedir. Ülkeler arasındaki bu farklılıkları yönlendiren unsurların ele alınması ülkelerin ekonomik yönden büyüyebilmesi ve kalkınabilmesi için anahtar faktörlerin belirlenmesi, sürdürülebilir büyümenin tesis edilmesine katkı sağlayacaktır. Bu nedenle çalışmada, gelişmiş ve gelişmekte olan üst orta ve alt orta gelirli ülkelerde 2006-2017 dönemi için yönetişim, inovasyon ve ekonomik büyüme arasındaki ilişki incelenmiştir. Çalışmada ele alınan değişkenler arasındaki ilişki, panel veri varsayımlarındaki sapmalara karşı dirençli bir tahminci olan Driscoll-Kraay tahmincisiyle test edilmiştir. Elde edilen sonuçlara göre; her üç ülke grubunda yönetişim ile büyüme arasında pozitif ve anlamlı bir ilişki, inovasyon ile büyüme arasında ise yalnızca gelişmekte olan üst orta gelirli ülkelerde pozitif ve anlamlı bir ilişki olduğu sonucuna ulaşılmıştır. Gelişmiş ve gelişmekte olan alt orta gelirli ülkelerde ise inovasyon ve büyüme arasında herhangi bir anlamlı ilişki tespit edilememiştir. Ayrıca yönetişim ve inovasyon ve büyüme ilişkisindeki aracılık etkisinin test edildiği araştırma modelinde ise her üç ülke grubunda da yönetişim ve inovasyonun büyüme üzerinde pozitif ve anlamlı bir etkisinin olduğu sonucuna ulaşılmıştır
AtıfOpenAlex5TR Dizin5İncele - MakaleAçık Erişim2023Prioritising and selecting the railway routes planned in the Eastern Black Sea Region with the AHP and TOPSIS methods
Boz, Ediz; Türk, Ersin; Togan, Vedat
The construction of the railway, which is needed for the development of the Eastern Black Sea Region, is an issue that has been discussed and unresolved for about 110 years. The geomorphological structure of the region and the developments in the highway played a role in the delay of the railway construction. However, the developing technology in the railway, Turkey's being a part of the Iron Silk Road Project, and the agreements made with international connections have brought the railway construction to the region again. In the Environmental Plan (EP) approved and in force by the Ministry of Environment, Urbanization and Climate Change, four railway routes are planned to integrate the Eastern Black Sea region with the national/international railway network. These routes are; Samsun-Sarp, Trabzon-Erzincan, Of -Erzurum and Tirebolu-Bayburt. However, some of these routes are alternatives to each other and are not feasible and rational since the implementation of all planned routes requires great costs. The aim of this study is to develop a method for prioritizing and selecting the railway routes planned in the EP. Within the scope of this purpose, by using Analytical Hierarchy Process (AHP) and TOPSIS techniques, which are multi-criteria decision making methods, the routes were listed according to 4 criteria and 10 sub-criteria determined with the help of literature and expert team. As a result of the study; In both techniques, the order was the same and it was determined that the Samsun-Sarp railway was the most priority railway route. Trabzon-Erzincan came second, Of-Erzurum came third and Tirebolu-Bayburt came fourth.
AtıfWoS3OpenAlex3TR Dizin2İncele
